1. Field of the Invention
This invention relates to a new organic ferromagnetic substance free of any ferromagnetic metal and to a process for producing same. More particularly, this invention relates to a new organic ferromagnetic substance which comprises a specific organic substance or a mixture of the organic substance and an auxiliary organic and/or inorganic material and is absolutely free from a ferromagnetic metal or an oxide thereof such as iron, cobalt, nickel, magnetite, etc. as well as to a process for producing same which comprises subjecting a polymer prepared from the specific organic substance with or without other auxiliary organic and/or inorganic material to a heat treatment in vacuo or in an atmosphere of an inert gas.
2. Description of the Prior Art:
Magnetic materials are used not only as magnets but also for manufacturing magnetic tapes or magnetic disks for use in computers for magnetic recording and memory. Besides these uses, magnetic materials are used for the elements and materials of audio equipment and for cards for credit, cash-dispenser and like purposes. Accordingly, magnetic materials are now widely utilized for various industrial fields and for civil life.
Hitherto, a ferromagnetic transition metal or a compound thereof, such as iron, cobalt, nickel and an oxide thereof, has generally been used as such magnetic materials and is applied onto a substrate made of an organic high molecular substance, for example, in the form of a tape, disk or card. According to a conventional method, such metallic magnetic material is applied onto substrates by way of sputtering or the like troublesome means. Recently, it was reported that an organic polymer obtained from (i) diacetylene carrying a nitroxy radial in the 1,4-position thereof, (ii) pyrene and benzaldehyde, or (iii) triaminobenzene and iodine, etc. exhibits ferromagnetic property and that an electric charge transfer complex of decamethylferrocene and tetracyanoethylene exhibits ferromagnetic property at 4.8K.
In Japanese Laid-open Patent Appln. No. Sho. 63-209522 there is disclosed that an organic polymer possessing ferromagnetic property is obtained by polycondensation of an aromatic aldehyde compound with a fused polynuclear aromatic compound in a magnetic field or by polycondensation followed by dehydrogenation of these compounds without using a magnetic field.
However, the starting materials of these organic ferromagnetic substances are limited to those carrying a specific organic radical or those of a specific aromatic series, and so are neither ordinary nor commercially available. Further, the above mentioned prior art encounters considerable difficulty in producing the organic ferromagnetic substances and has such a drawback that the substances are unstable in the air or against heat. In addition, the yield of the portion of the product exhibiting ferromagnetic property is extremely low (usually, less than 0.1%) so that these prior arts approaches are substantially of no practical value.
Under the circumstances, there is a great demand in this art for developing a new stable organic ferromagnetic substance which can be produced from commercially available ordinary starting materials according to a simple method.